The invention concerns a device for hardening the teeth of gear wheels by inductive heat treatment, the device comprising a rotary device for rotating the gear wheel about its central axis as well as comprising a radially movable hardening inductor for hardening the tooth bodies and/or tooth sass as well as subsequent quenching.
The device, in this connection, is suitable for gearwheels with an external toothing as well as with an internal toothing.
Depending on the application purpose of gear wheels, the individual teeth must be hardened. In case of large gear wheels, this is carried out in general by individual tooth hardening. In this connection, one must differentiate between hardening of the tooth tip, i.e., the tooth body, or—depending on the application purpose—the hardening of the tooth gaps.
Hardening of these large gear wheels increasingly is performed by means of induction heating devices. For this purpose, the gear wheels are clamped on a rotary device (in general, an NC axis).
Hardening is carried out by means of an inductor by heating a precisely defined zone of the tooth body with a defined heating depth to a precisely defined annealing temperature (hardening temperature). The immediately following quenching process by means of a suitable quenching medium (for example, water, possibly with certain admixed additives) hardens the teeth to a predetermined degree of hardness.
Performing this gear wheel hardening has been carried out up to now on machines with a single inductor. The hardening process is correlated with a significant time expenditure that—depending on the size of the gear wheel—may extend into the range of hours. In this connection, either directly adjacent tooth tips/tooth gaps are processed in a single revolution. Processing can however also be done with a defined spacing of the tooth tips/tooth gaps, i.e., every second, every third, every fourth tooth tip/tooth gap is hardened. In this way, the thermal influence of the neighboring teeth by the prior hardening process is reduced. In this method, the gear wheel must therefore be rotated completely several times.
Based on this, it is the object of the invention to provide a device for hardening the teeth on gear wheels by inductive heat treatment with which method the gear wheels can be hardened faster.